How to Make It
Combine the eggs, garlic, bread crumbs, paprika, cumin, 1¼ teaspoons salt, and ¼ teaspoon pepper in a medium bowl. Add the lamb and gently mix with your hands until just combined. Form the mixture into 18 meatballs (about 2 tablespoons each).
Heat the oil in a large pot or Dutch oven over medium-high heat. Cook the meatballs, turning occasionally, until browned all over, 4 to 6 minutes. (They do not need to be cooked through.) Transfer to a plate; reserve the pot.
Add the chard stems to the reserved pot. Cook, stirring, until crisp-tender, 2 to 3 minutes. Add the chicken broth and meatballs and bring to a boil. Reduce heat and simmer until the meatballs are cooked through, 10 to 12 minutes. Add the orzo and simmer until tender, 8 to 11 minutes.
Just before serving, fold in the chard leaves. Serve warm topped with the yogurt, if desired.